Last weekend I took a night trip out with the Suizo Project. The project’s hard working leaders use radio telemetry to record the movements and key life history traits of rattlesnakes living in the Suizo Mountains in Pinal County, Arizona, which is in the heart of the Sonoran Desert. You can view their Facebook page for project updates here. This was beautiful country and the time of year couldn’t be more perfect: the hot and humid monsoon which plagues the region every summer has officially ended (and so have the days which reach 100 degrees Fahrenheit by 10am and 108 by 3pm). While it still gets hot in the Valley of the Sun near Phoenix (100+, occasionally but not for long), down south in the mountainous Suizo area closer to Tucson (close to 3000 feet at the site I was told) it is simply lovely. The moon was a few days after full, and through the clear and dry desert sky the landscape glowed in a cool blue nightlight. Throughout the evening the temperatures stayed in the 70s and it was the type of night you spend on top of, but not inside, your sleeping bag.

After sundown we embarked on a five hour trek, meaning I followed the knowledgable and experienced guys around the desert and completely took advantage of their skill and expertise in order to learn a lot of things and take a few pictures (I’m not ashamed). Let me just say that in academia, I meet a lot of folks who know a lot about a lot of things but these. Guys. Know. Rattlesnakes. They are experts who can school anyone in the natural history of these incredibly fascinating species – the seasonality of their movements, their food preferences, their mating strategies, their evolution and the environment in which they live.

Some gratuitous musing:

Throughout the 20th century and into today, biology has evolved into ever more specific sub-disciplines, each noble in their own right yet many increasingly cordoned into a sterile laboratory or anonymous computer server, removed from the true natural world. I think the subject of natural history still has its place as a philosophy, a method and appreciation of understanding how the world works. It was after all what inspired me to become an evolutionary biologist.

A female tiger rattlesnake (Crotalus tigris). Note the cactus spines lodged into the scales on her face and torso (yes, snakes have a torso, there’s more to them than a head and a tail). Despite these difficulties, she was in a rather accommodating mood.

Nice shot of the same tiger rattler from above, to highlight its beautiful markings

Western Diamond-backed Rattlesnake (Crotalus atrox). I crossed the continent hoping to see these guys in their natural habitat, and I was ecstatic to see this one. While beautiful and wary of humans, it is extremely venomous (even more so than the other rattlers).

UPDATE [9/27/2013]: I received a response from Marty of the Suizo Project team, who corrected my summation of the relative potencies of rattlesnake venom:

…”extremely venomous, (even more so than other rattlers)” wouldn’t be how I’d describe their venom. They are more venomous, which can be measured in toxicity or volume, than many species of rattlesnakes in terms of volume but few when using LD50 values as a proxy of toxicity. Tiger rattlesnakes, on the other hand, have the most toxic rattlesnake venom but have a small venom yield. Tigers don’t bite people due to their habits and habitat, and relatively small geographic range, while diamondbacks have a comparatively large geographic range, often in close association with people, and are responsible for more human deaths in the U.S. than any other rattlesnake species. It could be said diamondbacks are ‘more deadly’ than other U.S. rattlesnakes…not as in ‘deadly’ in a comparison of toxicity but literally are more deadly because they bite and kill more people – the true measure of deadly!

Thanks for the important distinction, Marty. I wouldn’t want to give diamondbacks a bad name, although we must admit that sadly it is a lost cause…

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Marc Tollis

Ph.D. in Ecology, Evolutionary Biology and Behavior program from the City University of New York. Research in population genetics, molecular evolution and comparative genomics. Former music major. Married with child. From Queens and Brooklyn, lives in Tempe, AZ.